RCS Encrypted Talkgroups

dbelleperc · Post by **dbelleperc** » Thu Dec 06, 2007 4:57 pm

Well either I'm crazy or the RCS has disabled the DES on their encrypted talkgroups. I am listening to CVPD NARC, SDSO DES North and South in the clear. I'm lost on this and if anyone would like to chime in be my guess.

Post by **brandon** » Thu Dec 06, 2007 7:13 pm

The SDSO DES talkgroups seem to be in the clear a lot... at least whenever I monitor them they are. The main Sheriff talk group I remember routine encryption is the 'SID Intelligence' TGID.
From my past monitoring I noticed CVPD NET seems to go coded at night/weekends but during the day often in the clear.

Control · Post by **Control** » Wed Dec 12, 2007 1:06 pm

The encryption on digital sysstems makes the audio even harder to understand that the normal digital, so many agencies use it sparingly, if at all.

OSW · Post by **OSW** » Sun Dec 16, 2007 7:10 pm

Control wrote:The encryption on digital sysstems makes the audio even harder to understand that the normal digital, so many agencies use it sparingly, if at all.

This is incorrect with P25 digital voice. It is true with analog encryption, which is known as SecureNet and is characterized by what sounds like open squelch and then a sync beep at the end.

I maintain equipment that occasionally uses encryption over normal P25 operation and I can attest to there being absolutely no change in voice quality due to how voice is handled within P25.

Mikey · Post by **Mikey** » Tue Dec 18, 2007 5:46 pm

I would imagine since it's just 0s and 1s rearranged differently, encryption of digital audio should have the same audio quality as non-encrypted digital audio ... Orange County law enforcement has been running full-time encrypted P25 for years now.

OSW · Post by **OSW** » Thu Dec 20, 2007 10:31 pm

Mikey wrote:I would imagine since it's just 0s and 1s rearranged differently, encryption of digital audio should have the same audio quality as non-encrypted digital audio ... Orange County law enforcement has been running full-time encrypted P25 for years now.

Exactly. With analog SecureNet there's a double conversion process (analog voice to digital, encrypt it, then convert the digital back to analog and TX it) plus the CVSD algorithm is also to blame.

One of the reasons there may be less encryption is because the Investigations TGs are setup for "selectable" encryption meaning it's up to the user to switch over. If they switch to a Dispatch channel they have to switch the encryption switch back to the clear mode. These guys just want to use the radio so I wouldn't think they like the trouble of having to switch back and forth all the time. And as far as I know if you attempt to talk on any of the SO Dispatch channels or Tacs in encrypted mode the system will reject the attempt.